Poly(styrene-b-(ethylene-co-butylene)-b-styrene) triblock copolymer (SEBS) was selected for functionalization and cross-linking reaction to prepare the anion exchange membrane. The cross-linked quaternized SEBS (QSEBS-Cn) membranes were synthesized by simultaneous of quaternization and cross-linking of chloromethylated SEBS with α,ω-difunctional tertiary amines. The spacer groups of (-CH2-)n in diamines did affect the functionalization, micromorphology and properties of the resulting QSEBS-Cn membranes. The ionic conductivity of QSEBS-Cn membranes greatly increased and methanol resistance slightly decreased with increasing the length of spacer groups in the cross-linked structures from -(CH2)- to -(CH2)6-. Compared to the un-cross-linked QSEBS, the QSEBS-Cn membranes behaved much higher mechanical property, service temperature, chemical stability and thermal stability. Moreover, the hybrid composite membrane of QSEBS-C6 with 0.5% of graphene oxide could also be in situ prepared. This hybrid membrane had both relatively high ionic conductivity of 2.0 × 10(-2) S·cm(-1) and high selectivity of 7.6 × 10(4) S·s·cm(-3) at 60 °C due to its low methanol permeability.

Owing to high specific capacity of ∼250 mA h g, lithium-rich layered oxide cathode materials (LiNi CoMnO) have been considered as one of the most promising candidates for the next-generation cathode materials of lithium ion batteries. However, the commercialization of this kind of cathode materials seriously restricted by voltage decay upon cycling though Li-rich materials with high cobalt content have been widely studied and show good capacity. This research successfully suppresses voltage decay upon cycling while maintaining high specific capacity with low Co/Ni ratio in Li-rich cathode materials. Online continuous flow differential electrochemical mass spectrometry (OEMS) and in situ X-ray diffraction (XRD) techniques have been applied to investigate the structure transformation of Li-rich layered oxide materials during charge-discharge process. The results of OEMS revealed that low Co/Ni ratio lithium-rich layered oxide cathode materials released no lattice oxygen at the first charge process, which will lead to the suppression of the voltage decay upon cycling. The in situ XRD results displayed the structure transition of lithium-rich layered oxide cathode materials during the charge-discharge process. The LiNiMnO cathode material exhibited a high initial medium discharge voltage of 3.710 and a 3.586 V medium discharge voltage with the lower voltage decay of 0.124 V after 100 cycles.

A crosslinked quaternized poly(styrene-b-isobutylene-b-styrene)/graphene oxide composite anion exchange membrane showed high ionic conductivity and low methanol permeability.

The electrolyte additive plays an important role in determining the crucial properties of batteries such as cycling stability and safety. Compared to material development, research on electrolyte and interphase is still in the early stage for sodium ion batteries (SIBs). Herein, for the first time, succinic anhydride (SA) is investigated as a synergistic filming additive to fluoroethylene carbonate (FEC), and the lifespan of the dual‐additive Na/Na0.6Li0.15Ni0.15Mn0.55Cu0.15O2 (NLNMC) cell is significantly improved, maintaining capacity retention of 87.2% over 400 cycles at 1 C rate. For comparison, the batteries with only one of the two additives or without any additive show much inferior electrochemical performance. After the addition of SA, the interphase layer on the surface of cycled NLNMC material becomes uniform and stable, which contains more oxygen‐rich organic species and less NaF. Additionally, the addition of SA also has an impact on the interphase layer in the sodium anode part as indicated by electrochemical impedance spectroscopy (EIS) and energy dispersive spectrometer (EDS) results. Moreover, the online differential electrochemical mass spectrometry (OEMS) tests show the dual‐additive cell has less CO2 generation during the initial two cycles compared to that with only FECs which demonstrates another advantage of SA for practical application.

The design of the anode material is considered the core subject in manufacturing a battery system, among which, Li is a commonly used, ideal anode material. Normally, the electrolyte is decomposed on the Li metal anode to form a solid electrolyte interphase (SEI) layer. [4] Owing to this layer, the contact between the electrolyte and Li metal decreases, causing the batteries to be recyclable and efficient. During batteries cycling, however, a large volume expansion of the Li anode may lead to a rupture of the SEI layer, exposing fresh Li that could react with the electrolyte. The rupture of SEI therefore leads to a low coulombic efficiency (CE) and poor cycling stability. [5,6] Generally, the decomposition of Li salts in electrolytes results in the SEI layer that comprises inorganic compounds, while the electrolyte solvents are composed mainly of organic components. [7,8] Some researchers have reported that increasing the content of inorganics in the SEI layer is beneficial for improving its stability and mechanical strength. [9][10][11] Different strategies for modulating the Li anode interface were investigated, including the use of electrolyte additives and artificial SEI layers. [12][13][14][15][16][17][18] Among them, regulating the composition of the SEI layers by changing the solvation structure of Li + using electrolyte additives seemed simpler. [19] During the transfer of Li + through the SEI layer, Li + desolvation causes coordination anions and solvents to decompose and spontaneously form the SEI layer. [20][21][22][23] Unfortunately, most electrolyte additives themselves participate in the formation of the SEI layer. [24][25][26] Moreover, the effect of the additives gradually disappears owing to their continuous decomposition. By contrast, the artificial SEI layers, where extra protective layers are grafted directly onto the surface of Li metal, will not decompose significantly as the batteries cycle. Instead, the artificial SEI layer inhibits the growth of dendrite because of its specific mechanical properties. [27][28][29][30] In addition, it helps disperse Li + after passing through the membrane, homogenize the flux of Li + , and reduce the formation of dendrites. [31][32][33][34] Due to the remarkable effect of artificial layers, previous researches on the nature of the protective layers themselves are intense. [35][36][37][38][39] However, it should be noted that artificial layer has always a certain lifetime, and we suppose Li metal has been attracting considerable attention as the most promising anode material for application in next-generation Li rechargeable batteries. However, the instability of the formed solid electrolyte interphase (SEI) in the Li metal anode leads to a low coulombic efficiency (CE). Here, two kinds of synthesized polymer materials with different molecular configurations (chain and cross-linked), which are grafted as skins on Cu foils (current collectors), are reported. The interaction between the polymers and electrolyte solvent reduces the amount of the solvent used in...

Li metal is a promising anode material for next-generation energy storage systems owing to its high theoretical capacity and low potential. However, uncontrollable Li dendrite growth during Li plating and...

The safety issue of lithium‐ion batteries is a crucial factor limiting their large‐scale application. Therefore, it is of practical significance to evaluate the impact of their overcharge behavior because of the severe levels of oxygen release of cathode materials during this process. Herein, by combining a variety of in situ techniques of spectroscopy and electron microscopy, this work studies the structural degradation of LiNi0.8Co0.1Mn0.1O2 (NCM811) accompanying the oxygen release in the overcharge process. It is observed that a small amount of O2 evolves from the initial surface at ≈4.7 V. When charging to a higher voltage (≈5.5 V), a large amount of O2 evolves on the newly formed surface due to the occurrence of microcracks. Based on experimental results and theoretical calculations, it is determined that the oxygen release mainly occurs in the near‐surface regions, where the remaining oxygen vacancies accumulate to create voids. To suppress the oxygen release, single‐crystalline NCM811 with integrated structure is introduced and serves as a cathode, which can effectively inhibit morphology destruction and reduce the activation of lattice oxygen in the surface region. These findings provide a theoretical basis and effective strategy for improving the safety performance of Ni‐rich cathode materials in practical applications.

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